Input shafts, and in particular transmission input shafts, generally transfer power from a power supply source to a means of output device, such as a gearbox, transfer box or the like. A transmission input shaft obtains the turning motion from the engine and is engaged to an output device such as a clutch assembly or overdrive clutch assembly. These input shafts are normally supported for rotation by bearings in the transmission housing forward wall and have a first inwardly extending end carrying an input gear and a second outwardly extending end provided with external splines for receiving the internal splines of a driven hub of a coupling member, such as a master friction clutch or torque converter that directly connects the transmission input shaft to the vehicular engine.
A transmission input shaft has a bushing slot that allows oil to flow from the central bore of the transmission input shaft to a portion of the clutch assembly for providing lubrication to the clutch assembly. The bushing slot provides oil at a very slow rate and fails to provide adequate heat dissipation from the steel reaction plates in the clutch assembly. The extreme heat generated during the initial clutch apply on the 3-4 upshift will quickly cone or warp the steel reaction plate/friction plate. Once the reaction plate begins to warp, it then creates drag when it is not applied during the 1st, 2nd, and 3rd gears. The drag inadvertently partially applies the overdrive clutch when it should not be applied. The warping causes further warping and eventual total failure.
It is an object of the present invention to provide an input shaft that can provide a requisite and consistent amount of oil to a clutch assembly or other attachment to provide adequate lubrication and heat dissipation.